Excavators



Nov. 23, 1965 R. o. BIQLLINGS EXGAVATORS 2 Sheets-Sheet 1 Filed July 6, 1962 INVENTOR R.O. Billings A11 om eys Nov. 23, 1965 R. o. BILLINGS EXCAVATORS 2 Sheets-Sheet 2 Filed July 6, 1962 INVENTOR R.O. Billings Asa-[5 0w No Ai 3 8 m Attorneys United States Patent 3,219,212 EXCAVATORS Roy 0. Billings, Box 2611, Milwaukee, Wis.

Filed July 6, 1962, Ser. No. 207,945 9 Claims. (Cl. 214-135) This invention relates to improvements in excavators, and more particularly to an excavator which can be readily furnished as a trailer and operatively attached to any type of pulling vehicle, and which excavator has improved digging and lifting means.

The present invention is intended to provide a novel excavator which combines the mobility and versatility of a backhoe with the greater digging capacity and efiiciency of a clam shell excavator, the present structure being an improvement upon the device disclosed in my Patent No. 3,143,228, issued August 4, 1964. In addition to the basic unit disclosed in said prior patent, the present invention features a novel self-contained trailer unit which includes new structural innovations and improvements in the digging apparatus, and also includes novel, integral mounting and power assemblies which permit its use with any conventional type of pulling vehicle, including jeeps, tractors and trucks of various makes and models.

In recent years the use of mobile, trailer-type digging equipment has grown substantially due to the increased volume of highway and similar construction projects, and while such equipment has been improved over the years, presently-available excavators of this type are not entirely satisfactory for their intended purposes. For one thing, those trailer-type excavators which are designed for use with power take-off devices of tractors are handicapped by the relatively low hydraulic pressure systems ordinarily characterizing that type of vehicle. Moreover, and with trucks as well as tractors, the power takeoff and frame constructions of such pulling vehicles vary widely with the different makes and models, and special excavator frame units have to be designed and built for each particular vehicle style. For this reason, one of the principal objects of the present invention, as hereinabove mentioned, is to provide a novel excavator which can be readily attached to any conventional type of pulling vehicle, and wherein the excavator is a complete, independent unit with its own power plant and high pressure hydraulic system, thus eliminating the necessity for relying on the widely varying and frequently inadequate power systems ordinarily provided in tractors and other pulling vehicles.

A more specific object of the present invention is to provide a trailer-type excavator having an integral mounting adapter plate thereon which is provided with a multiplicity of bolt apertures to permit the unit to be readily bolted to the frame of any type of pulling vehicle, and which apertured plate also functions as a ventilator for the excavator power plant and hydraulic system.

A further specific object of the present invention is to provide an improved excavator of the type disclosed in my prior, copencling application, Serial No. 59,577 (now Patent No. 3,143,228), and which improved machine is provided with a specially-designed boom and turntable assembly adapted to substantially increase the efliciency, effectiveness and durability of the digging apparatus.

A further specific object is to provide an improved excavator having specially-designed means for stabilizing the loaded digging bucket during lateral movement of the boom and during the discharging operation, thereby enhancing the effectiveness of the machine.

A further specific object of the invention is to provide a trailer-type excavator having a specially-designed extendible outrigger assembly adapted to support and stabilize the machine during the digging operation, said outrigger assembly having caster wheels which are extendible with the outrigger and which also support the trailer during transit.

A further object is to provide a novel excavator having specially-designed dipstick and bearing elements which are readily adjustable to compensate for wear.

Still further objects of the present invention are to provide an improved trailer-type excavating machine which will outperform presently-available excavators of comparable size, and which improved excavator is substantially less expensive to manufacture.

With the above and other objects in view, which other objects and advantages of the present structure will become apparent hereinafter, the invention consists of the improved trailer-type excavator, and all of its parts and combinations, as set forth in the specification and claims, and all equivalents thereof.

In the accompanying drawings, wherein there is shown one preferred embodiment of the invention, and wherein the same reference numerals designate the same parts in all of the views:

FIG. 1 is a side elevational view of the improved excavator attached to the rear of a pulling vehicle;

FIG. 2 is a top plan view of the excavator taken along line 22 of FIG. 1;

FIG. 3 is a fragmentary front view of the excavator looking inwardly along the line 33 of FIG. 2, and showing the extended position of the outriggers in dot and dash lines;

FIG. 4 is a top plan view of the boom turntable with the boom disconnected;

FIG. 5 is a transverse sectional view through said turntable, taken along line 55 of FIG. 4;

FIG. 6 is a sectional view taken on line 66 of FIG. 1; and

FIG. 7 is a fragmentary front elevational view illustrating the caster wheel arrangement.

General construction and operation The construction and operation of the boom and dipstick portion of the present machine is basically similar to that described in the aforementioned Patent No. 3,143,- 228, which is incorporated herein by reference, and the common elements will therefore be described only in a general manner, the improved features being described in greater detail hereinafter.

With reference first to FIG. 1, the numeral 10 designates the rear end portion of a tractor or similar towing vehicle to which the improved excavator trailer comprising the present invention may be attached during use. Projecting rearwardly from said tractor are rigid struts 13 which are part of the supporting frame of the excavator, and mounted in an offset position on said frame is a cab 14 in which the operator sits, and which houses the various hydraulic and engine controls. Extending laterally from the sides of the device below the cab 14 are extendible outrigger arms 15 (FIGS. 2 and 3), and carried on the outer ends of said arms are hydraulically operated foot assemblies 17 which may be lowered to support the excavator during the digging operation, as will be described. Between the cab and adapter plate 12 a suitable motor 9 for driving a high pressure pump 10 may be mounted, the latter furnishing fluid pressure for the rams, as is well known in the art.

The apparatus includes a hydraulically actuated turntable 20 (FIG. 2) having a pivotal boom 30 projecting rearwardly and upwardly therefrom, and a double-acting hydraulic cylinder and ram 31 is pivotally secured to and between said boom and the frame to provide means for pivoting said boom in a vertical plane. A sheave 32 is rotatably carried on the inner end of the boom, and carried on the boom outer end is a pair of coaxial sheaves 33 and 34, said sheaves being rotatably mounted on shaft 37. Also pivoted to said boom as at 35' is a doubleacting ram 35 having a sheave 36 on its inner,.free end which is designed to move longitudinally inwardly along the boom when said ram is extended. Pivotally mounted on the shaft 37 at the outer end of the boom 30 is a bearing sleeve 40, there being a double-acting hydraulic ram 49 pivotally connected between the boom 30 and sleeve for pivoting the sleeve and dipstick in a vertical plane; and slidably carried in said sleeve is the dipstick 46.

Anchored to the boom at a point intermediate its length, as at 50, is one end of a cable 51 which is trained about the aforementioned movable sheave 36 and under the sheave 34 on the boom outer end, said cable extending upwardly along the upper end of the dipstick and being anchored to the upper end thereof as at 52. A second cable 54, which has one end anchored to the extendible ram 35 at 55 (FIG. 2), is trained about the inner sheave 32 and over the sheave 33 on the boom outer end, the latter cable extending downwardly along the dipstick and being anchored to the lower end thereof as at 56. As will be readily appreciated, when the hydraulic ram 35 is extended, the sheave 36 thereon moves inwardly and the cable 51 pulls downwardly on the dipstick. Simultaneously, said extensible movement of said ram pays out cable 54 to allow such downward movement of the dipstick. When the double-acting ram 35 is retracted, a reverse operation is provided. In the latter case, the retracting movement of said ram causes the cable 54 to pull the dipstick upwardly, such ram movement simultaneously paying out the cable 51 to permit the upward travel of the dipstick through the sleeve 40.

The digging bucket (FIG. 1) in the present unit is preferably identical to the bucket disclosed in the before-mentioned copending application, said bucket including radial shoulders 61 on its top surface against which the dipstick foot 4 7 bears during the digging operation, and said dipstick and bucket being flexibly joined by links 48, Said bucket also includes clam shell digging members 62 which have hydraulic actuating rams associated therewith to effect opening and closing of the same, as is fully described in said prior patent application.

In the use of an excavator of the type illustrated, the tractor or other vehicle to which the unit is attached is moved adjacent the area to be excavated and the excavator boom 30 is swung horizontally to a position directly over the intended digging area, through the operation of the turntable 20, as will be hereinafter described. The rams 31 and 49 are then actuated to obtain the desired boom and dipstick angles, and the dipstick 30 is lowered by the aforementioned cable and sheave assemblies to a position where the digging bucket 60 engages the earth, operation of the clam shell elements 62 causing the same to bite into the ground. When sufficient dirt has been collected in the bucket the dipstick and boom are raised and swung laterally to a discharge position over a dump truck or the like.

As is brought out in my prior Patent No. 3,143,228, due to the independently movable nature of the boom, dipstick and digging bucket characterizing the present type of excavator, a wide variety of operative angles can be obtained. Moreover, positive digging force can be applied to the digging bucket at any angle through the vertically movable, rigid dipstick 46, thus providing a novel machine which combines the advantageous features of both a conventional clam shell and backhoe type of excavator.

Mounting assembly As mentioned, one of the important characteristics of the present excavating machine is that it can be easily attached to any conventional type of pulling vehicle, including jeeps, tractors, or trucks of various makes and styles. In this respect, attention is directed to FIG. 1 of the drawings, wherein the excavator is shown coupled to the rear of a tractor 10. The illustrated tractor has a plurality of rigid mounting arms 11 supporting an apertured plate 11. Some tractors and other towing vehicles include trailer mounting arms similar to said arms 11 as standard equipment, or they have other frame end portions to which the improved trailer can be bolted. In the event the vehicle does not have suitable trailer mounting means, arms similar to the illustrated arms 11 can be suitably secured to the frame. The mounting assemblies ordinarily provided on towing vehicles vary in size, spacing and location on different makes and types of vehicles.

In accordance with the present invention, a large, vertically disposed, rectan ular adapter plate 12 is permanentlly' carried on the forward end of the trailer frame members 13. Said adapter plate is provided with a multiplicity of apertures 12' (FIG. 3), and due to the size and spacing thereof some of said apertures will correspond to and register with the mounting arm apertures on any type of towing vehicle, thus permitting the quick and simple attachment of the improved trailer-excavator to pulling vehicles of any make or style. A mounting adapter plate 12 having approximately four hundred and fifty bolt holes therein, each being about inch in diameter, has been found to be especially satisfactory.

Unlike prior trailer-type excavators, the present trailer is provided with its own high pressure, split flow hydraulic system, including a motor 9, pump 10, and reservoir 8, thereby eliminating the necessity for relying on the low pressure hydraulic systems ordinarily incorporated in tractors and similar pulling vehicles, and which low pressure systems are inadequate for excavating purposes, the present trailer-excavator being operationally independent of its pulling vehicle. Said engine and hydraulic pump units are preferably mounted on the trailer in the space between the adapter plate 12 and cross member 15 as indicated diagrammatically in FIG. 2 and, in addition to its primary function as a mounting member, said apertured plate also functions as a ventilator for said engine and pump members, thus minimizing the possibility of over-heating.

Outrigger assembly As hereinabove mentioned, the improved trailer-excavator comprising the present invention is provided with a novel outrigger which is designed to support and stabilize the machine both during the digging operation and during transit. Said outrigger includes telescopic arms 15 which are extendible from their normal, retracted position within a tubular cross member 15, as shown in FIG. 2 and in full lines in FIG. 3, to the extended position shown in broken lines in FIG. 3, said arms being hydraulically actuated and there being suitable remote control means in the operators cab. Carried on the outer end of each of said arms 15 is a vertical leg 16 having a hydraulic ram 17 therein, and attached to the lower end of each of said rams is a foot 18 which is normally carried in spaced relation above the ground. Said feet 18 are designed to support the machine during its digging and lifting operation, as will be hereinafter seen. The arms 15 and rams 17 for the feet 18 may be arranged and operated in any suitable. manner such as the way illustrated in FIG. 1 of my prior Patent No. 2,365,169, dated December 19,

As best appears in FIGS. 1 and 2, brackets 65 are hingedly attached to and project rearwardly from said outrigger legs 16, and mounted on and depending from each ofsaid brackets is a pair of pneumatic, groundengaging swivel caster wheels 66 which furnish support during transportation. Said brackets 65 are pivotal in a vertical plane about pins 67, and against compression springs 68 which function as shock absorbers and compensate for unevenness in the ground when the machine is in transit. The compression springs 68 surround rods 85) which project from the legs 16 and which are slidable through enlarged openings in back walls of the brackets 65, as is clear from FIGS. 2 and 3. Each spring acts between loose washers 82 and 81, and the latter in turn reacts against the rear wall of the bracket to yieldingly resist pivotal movement of the bracket 65 on the pins 67. The action of the springs may be adjusted by manipulation of nuts 83. Each pair of pneumatically-tired caster wheels 66 is mounted on axle studs 84 extending in opposite directions from the lower end of a caster leg 85, as is shown in FIG. 7. The upper end of each caster leg is swivelly connected as at 86 to the bottom of the bracket 65, as is clear from FIG. 7.

When the trailer-excavator comprising the present invention is to be transported, the outrigger arms are ordinarily retracted to minimize the width of the unit on the highway. Due to the swivel mounting of the caster wheels 66 said trailer can turn easily with the tractor or other pulling vehicle to which it is rigidly attached, and can follow said pulling vehicle around sharp corners without danger of overturning.

When the machine is to be used for excavating, the outrigger arms 15 are extended to the broken line position of FIG. 3, the swivel caster wheels permitting such lateral movement and moving outwardly therewith, and the hydraulic rams 17 may be then lowered until the feet 18 thereon barely contact with the ground. When the digging bucket is filled with dirt, the weight of said bucket and the boom compresses the pneumatic tires 66 just enough so that said outrigger feet 18 take the load. When the bucket is emptied, however, the tires again assume their normal condition and the outrigger feet 18 are again barely touching the ground. Thus, after a load of dirt has been emptied into a dump truck or the like, theexcavating machine may be moved and it is not necessary to lose any time in retracting the vertical outrigger legs.

Turntable The boom-supporting turntable assembly 20 is especially designed and constructed to provide improved bearing in all boom positions, and to provide increased support and stability for the loaded digging bucket. As best appears in FIGS. 2, 4 and 5, said turntable member 21, somewhat larger than a semi-circle, is rotatably mounted on a vertical center pin 22 projecting upwardly from and supported by the rigid portion 15' of the trailer frame, there being a sealed ball bearing unit 23 surrounding the upper portion of said center pin, the lower portion of said bearing being carried by the pin 22 and the upper portion being carried by the turntable whereby the latter is rotatable around the pin. Said disc 21 has a curved plate 24 depending therefrom which is secured to a bushing 25 and to a sprocket 26 rotatably surrounding the lower portion of the rigid center pin 22. A pair of hydraulic rams 28 on the frame are connected to said sprocket 26 by a chain27 (FIG. 1) and are adapted to swing said disc unit to effect lateral swinging movement of the boom in either direction.

The upper part of said ball heating unit 23 is pivotally connected to the turntable disc by means of a pair of horizontal pins 76 (FIG. 4) which pins have outer ends pivoted to upright brackets 76' on the disc 21. Thus said turntable disc is tiltable on a horizontal axis of said pins 76 within limits. This slight tilting or tipping movement of the turntable disc compensates for variations in the roller track 21 and assures perfect alinement in all positions.

As is shown in FIGS. 4 and 5, three stationary hook roller assemblies are mounted in spaced relation around and adjacent the periphery of the disc 21, said assemblies being designed to ensure that the turntable does not tip under load and assuring perfect alinement in all positions. Said roller assemblies include upright supporting arms 29 which are rigidly mounted on the outrigger frame portion 15, and rollers 29 which extend over the disc and normally engage the upper surface of a raised rim or track 21' formed on the outer, marginal portion of said disc. Said roller assemblies are designed to prevent tipping of the disc 21 and serve to stabilize the same during lateral swinging movement of the boom, and particularly when the digging bucket is loaded. In such instances, the weight on the forward edge of the disc 21 is substantial and tends to tip said disc forwardly, putting considerable strain on the center pin 22. Due to the presence of said hook rollers 29, however, upward movement of the disc at any point diametrically opposite the boom is resisted, and such tipping or tilting action is minimized. As the disc and boom rotate, different sets of said stationary roller bearings are brought into play, and the circumferential spacing of said members ensures effective support throughout the arcuate movement "of the boom. The unique turntable stabilizing device thus provided is also important during the bucket discharging operation, when the momentum is reversed upon discharge of the load and the tipping force is momentarily accentuated.

The boom 30 utilized in the present machine projects rearwardly and upwardly from the turntable 20, as hereinabove described, and the lower, forward end of said boom is pivotally anchored to said turntable as at 70 through the medium of upwardly-projecting boom feet 71 on the turntable which also pivotally support the hydraulic boom actuating ram 31. Said boom feet have cutouts in their lower portions as shown in FIG. 5 to accommodate the aforementioned ball bearing assemblies 23. Said ram 31 is designed to move the boom 30 in a vertical plane about its turntable connection 70 to obtain the desired boom angle for digging and dumping. Like the other hydraulic members hereinabove described, said ram 31 can be remotely operated and controlled by the operator from the cab 14. It is to be noted that the otherwise circular turntable 21 has a cut-off rear portion and that the boom is pivoted to the turntable close to said cut-oflf rear portion at points which are substantially closer to the center pin than are the roller sets 29. As a result, the weight of the load on the boom acts on a relatively short lever arm at the turntable and the rollers 29 have a substantial stabilizing etfect due to their greater distance from the center pin.

Dipstick and sleeve The rigid dipstick 46 in the present machine is slidably carried in a sleeve bearing 46 on the outer end of the boom, said dipstick being movable upwardly and downwardly through said sleeve in response to operation of the aforementioned cable and sheave assemblies.

As is shown in FIG. 6 of the drawing, the dipstick 46 in the present invention is I-shaped in cross section, the flange portions having beveled inner longitudinal surfaces 41', as illustrated. The sleeve 40 within which said dipstick moves is provided with pairs of tapered guide rollers 41 which are designed to engage the similarly-tapered inner surfaces 41 of the stick member to provide rolling engagement therewith, there being two pairs of said rollers on each side of the dipstick. Said sleeve 40 is formed of two spaced side plates 42 which are rotatably mounted on the shaft 37 supporting the aforementioned sheaves 33 and 34, and connecting said plates are adjustment bolts 43 having nuts 44 and 45 thereon clampingly engaging the plates 42 therebetween.

When either the guide rollers 41 or the surface of the dipstick 46 in the present invention become worn, said rollers may be readily adjusted to compensate for such wear and to ensure the proper sliding movement of the stick without too much play. To accomplish this it is merely necessary to loosen the inner clamping nuts 45 and manually move the sleeve plates 42 closer to each other, also loosening and moving the sheaves 33 and 34 closer together if necessary, and then tightening the outer nuts 44 against the adjusted plates, thereby shifting said tapered rollers -41 inwardly and into closer engagement with the beveled faces 41' of the dipstick flanges, and again establishing firm rolling contact therebetween.

The simplified open sleeve and stick construction provided in the present machine is also advantageous in that it is considerably less expensive to manufacture than prior stick and sleeve assemblies, and it also clears itself of dirt and rust, thereby eliminating a source of constant trouble in prior devices.

From the foregoing detailed description, it will be seen that the present invention provides a trailer-excavator combining the mobility and versatility of a backhoe with the digging capacity and efliciency of a clam shell excavator, the said device having improved features including novel caster wheel outriggers which furnish wheel support when the device is being moved and which nevertheless permit easy adjustment of the outriggers.

With the above in mind, it is intended that the present invention include not only the embodiment illustrated and hereinabove described, but also any and all modifications or changes therein as may come within the spirit of the invention and within the scope of the following claims.

What I claim is:

1. In combination with a pulling vehicle, a trailer having a frame and having a work performing element carried thereby, means rigidly connecting said trailer frame to said pulling vehicle, horizontally disposed outrigger members supported on said trailer frame for lateral movement, caster wheels on the outer portions of said outrigger members positioned to furnish rolling support to the trailer during transit and movable with the outriggers, and movable ground engaging feet at the ends of said outrigger members movable from a position above the ground to a position to take the load off of said wheels When work is to be performed.

2. In combination with a pulling vehicle having a rear frame part with apertures, a trailer having a frame and having a work performing element carried thereby, a coupling plate at the front of said trailer frame having a multiplicity of apertures, some of which register with apertures of said frame part of the pulling vehicle, bolts extending through said registering apertures for effecting rigid connection of said trailer frame to said pulling vehicle, horizontally disposed outrigger members supported on said trailer frame for lateral movement, caster wheels on the outer portions of said outrigger members positioned to furnish rolling support to the trailer during transit and movable with the outriggers, and movable ground engaging feet at the ends of said outrigger members movable from a position above the ground to a position to take the load off of said wheels when work is to be performed.

3. In combination with a pulling vehicle having a vertically disposed, rearwardly facing frame part with apertures, a trailer having a frame and having a Work performing element carried thereby, a vertically disposed, transverse coupling plate at the front of said trailer frame having a multiplicity of apertures, some of which register with apertures of said frame part of the pulling vehicle, bolts extending through said registering apertures for effecting rigid connection of said trailer frame to said pulling vehicle, horizontally disposed outrigger members supported on said trailer frame for lateral movement, caster wheels on the outer portions of said outrigger members positioned to furnish rolling support to the trailer during transit and movable with the outriggers, and movable ground engaging feet at the ends of said outrigger members movable from a position above the ground to a position to take the load off of said wheels when work is to be performed.

4. In a trailer having a frame and having a work performing element carried thereby, connecting means for effecting connection of said frame to a pulling vehicle, horizontally disposed outrigger members supported on said frame for lateral movement, caster wheels on the outer portions of said outrigger members positioned to furnish rolling support to the trailer during transit and laterally movable with the outriggers, and movable ground engaging feet at the ends of said outrigger members movable from a position above the ground to a ground engaging position to take the load off of said wheels when work is to be performed and When the outrigger members are laterally extended.

5. In a trailer-excavator having a frame and having a boom supporting turntable rotatably mounted on said frame, means for effecting connection of said frame to a pulling vehicle, horizontally disposed outrigger members supported on said frame for lateral movement, caster wheels-on the outer portions of said outrigger members positioned to furnish rolling support to the trailer during transit and laterally movable with the outriggers, and movable ground engaging feet at the ends of said outrigger members movable from a position above the ground to a ground engaging position to take the load off of said wheels when work is to be performed and during rotation of said turntable.

6. In a trailer having a frame and having a work-performing element carried by said frame, means for detachably effecting connection of said frame to a pulling vehicle, outrigger members on opposite sides of said frame, means movably supporting said outrigger members for lateral movement, caster wheels swivellingly mounted on said outrigger members and positioned to furnish rolling support for the trailer during transit and laterally movable with the outrigger members, and feet supported at the outer ends of said outrigger members for movement from a position above the ground to a ground-engaging position to take the load off of said wheels when work is to be performed.

7. In a boom-supporting trailer having a frame and having a work-performing element carried by said boom, means for detachably effecting connection of said frame to a pulling vehicle, outrigger members on opposite sides of said frame, means movably supporting said outrigger members for lateral movement, caster wheels swivellingly mounted on said outrigger members and positioned to furnish rolling support for the trailer during transit and laterally movable with the outrigger members, and feet supported at the outer ends of said outrigger members for movement from a position above the ground to a groundengaging position to take the load off of said wheels when work is to be performed.

8. In a boom-supporting trailer having a frame and having a work-performing element carried by said boom, means for detachably effecting connection of said frame to a pulling vehicle, outrigger members on opposite sides of said frame, means movably supporting said outrigger members for lateral movement, a bracket projecting from each outrigger member, caster wheel means swivellingly depending from each bracket and positioned to furnish rolling support for the trailer during transit and laterally movable with each outrigger member, and feet supported at the outer ends of said outrigger members for movement from a position above the ground to a ground-engaging position to take the load ofi of said wheels when work is to be performed.

9. In a boom-supporting trailer having a frame and having a Work-performing element carried by said boom, means for detachably eifecting connection of said frame to a pulling vehicle, outrigger members on opposite sides of said frame, means movably supporting said outrigger members for lateral movement, a bracket pivoted to each outrigger member for pivotal movement on a horizontal axis, yielding means normally resisting said pivotal movement of each bracket, caster Wheel means swivellingly depending from each bracket and positioned to furnish rolling support for the trailer during transit and laterally movable with each outrigger member, and feet supported 9 at the outer ends of said outrigger members for movement from a position above the ground to a ground-engaging position to take the load off of said wheels when work is to be performed.

References Cited by the Examiner UNITED STATES PATENTS 1,954,119 4/1934 Darrah 214-135 2,211,194 8/1940 Baker 214-135 2,387,087 10/1945 Pilch 212-66 Howard 180-536 Graham 212-145 Thacker 212-145 Sowell 214- Perkins et a1.

McQuire et a1. 212- Dorkins 212-67 Janson et a1. -12 X Nelson 212-66 10 HUGO 0. SCHULZ, Primary Examiner. 

1. IN COMBINATION WITH A PULLING VEHICLE, A TRAILER HAVING A FRAME AND HAVING A WORK PERFORMING ELEMENT CARRIED THEREBY, MEANS RIGIDLY CONNECTING SAID TRAILER FRAME TO SAID PULLING VEHICLE, HORIZONTALLY DISPOSED OUTRIGGER MEMBERS SUPPORTED ON SAID TRAILER FRAME FOR LATERAL MOVEMENT, CASTER WHEELS ON THE OUTER PORTIONS OF SAID OUTRIGGER MEMBERS POSITIONED TO FURNISH ROLLING SUPPORT TO THE TRAILER DURING TRANSIT AND MOVABLE WITH THE OUTRIGGERS, AND MOVABLE GROUND ENGAGING FEET AT THE ENDS OF SAID OUTRIGGER MEMBERS MOVABLE FROM A POSITION ABOVE THE GROUND TO A POSITION TO TAKE THE LOAD OFF OF SAID WHEELS WHEN WORK IS TO BE PERFORMED. 